The present invention relates generally to a rack or holding device for test tubes, such as culture tubes, analysis test tubes and the like, which permits extensive manipulation or transportation of the tubes held in the rack in a safe and secure manner, preventing rattling or dislodging of the tubes from the rack, while still permitting easy manual removal of the tubes from the rack.
In various methods of biological or chemcial analysis and culture testing, extensive handling, manipulation and transportation of rack-held test tubes or culture tubes may take place. It is therefore highly desirable that the test tubes be held securely in position in the holder or rack during manipulation and transportation such that, even though the rack may be upset or upturned, the test tubes do not become dislodged from their position in the rack.
Test tubes or culture tube holders or racks have been designed in the past comprising metallic spring clip means disposed about the apertures in the holder or rack support plate members, as disclosed, for example, in U.S. Pat. Nos. 1,188,146, 3,175,695 and 3,142,385. Such arrangements are generally complex, they provide test tube grasping means engaged only with a portion of the periphery of the tubes, and they may even cause applying too great a pressure on a small area of a relatively fragile tube, thus creating a potentially dangerous situation. U.S. Pat. No. 3,186,556 discloses a test tube rack in which the test tubes are disposed in deeply recessed pockets and held in the pockets by means of a U-shaped metallic spring disposed longitudinally alongside each test tube, and thus does not remedy any of the prior art inconveniences.
The present invention remedies the shortcomings and inconveniences of the prior art by providing a simple rack structure for test tubes and the like consisting of at least a pair of apertured plate members held in spaced parallel relationship and provided with an array of aligned apertures, one plate member, for example the bottom plate member, having each aperture provided with a groove in which is inserted a toroidal elastic element, such as an O-ring, having an internal diameter slightly smaller than the outer diameter of the test tubes, such that when a test tube is pushed through the aperture, it is held in position as a result of its periphery being frictionally and elastically engaged with the inside surface of the O-ring.
Alternatively, the present invention provides a test tube rack adapted to provide to an observer a visual indication of the status of an analysis or other experiment. For that purpose, an embodiment of the present invention contemplates forming a rack with at least a pair of parallel spaced apart apertured plates mounted above a base plate, each of the apertured plates having corresponding arrays of mutually aligned apertures each provided with a groove having a toroidal resilient member disposed therein. In such an arrangement, the depth of penetration of the test tubes within the rack may be manually adjusted such that the status of a manipulation, analysis or experiment may be judged visually as a function of the vertical positioning of the test tubes. In addition, the distance separating the apertured plates may be used as a gage of liquid level in the test tubes, or for any other purpose found suitable.